Liquid in a container is often pressurized by contact with a higher pressure gas in order to facilitate the passage of the liquid out of the container. Generally, the gas employed is carbon dioxide. This is especially the case when the liquid is a carbonated liquid such as beer. For example, when beer is contained in a keg, higher pressure carbon dioxide is passed into the keg and serves to increase the flowrate of the beer out from the keg over the flowrate which would otherwise occur. This enhances the speed and efficiency of the pouring operation.
A problem with the conventional pressurization and pouring method is that considerable froth or foam is generated during the pouring, reguiring a time loss to await dissolution of the foam and/or the waste of some liquid if the foam must be discarded. When the liquid is beer, a certain amount of foam or head is desired as being aesthetically pleasing. However a large head on a glass or mug of beer is wasteful and counterproductive. The problem of excessive foaming of keg beer is especially troublesome during peak demand periods when time cannot be spent to reduce beer loss due to foam.
Accordingly it is an object of this invention to provide a method and tapping agent to enable the pressurized passage of a liquid out from a container with reduced foam generation.
It is a further object of this invention to provide a gas mixture and method to pressurize a beer keg to enable enhanced flow of beer out of the keg with the generation of an aesthetically pleasing but not excessive head.